What are the Symptoms of a Cracked Cylinder Block?

The engine block or cylinder block is a most important part of the engine. It is made of durable metal. It contains a combustor, head gasket, piston, and other internal parts of the engine. A cracked cylinder block is very dangerous for your engine. There are multiple causes of a cracked engine cylinder block. A cracked engine cylinder block can show different signs of failure. This article explains the function, symptoms, and causes of a crack engine block.

What is a Cylinder Block?

The cylinder block is an engine part that contains the combustion chamber, piston, and other internal components of the engine. The cylinder block is also known as an engine block.

The proper operation of the cylinder block ensures the efficient working of the engine. When the block works efficiently, the piston moves upward and downward, which further turns the crankshaft. As the crankshaft gets rotation, it turns the vehicle wheels.

engine block
Image Refer (counterman.com)

The engine block is a sloid part made of high-quality iron or high-quality aluminum. The engine cylinder has a smooth and round shape installed in the engine block. This round shape of the cylinder allows the piston to move downward and upward with negligible friction. The engine oil is used to lubricate the piston and other parts of the cylinder block. All moving parts generate a lot of heat—the coolant and oil help to remove the heat of the moving parts.         

The proper operation of the blocks extends the life cycle of the vehicle. However, as something go wrong, the engine block can crack. As the block cracks, you need to replace it as soon as possible.                                                                                                                            

Signs of Cracked Cylinder Block

As the engine cylinder block fails or cracks, it gives one of the below-given signs. As you observe the signs of a cracked engine block, immediately contact the nearest mechanics to repair or replace the block.

1) Engine Smoke

The engine may emit smoke due to multiple reasons. If your engine emits dark gray or black smoke, this shows that your engine block has been cracked. This smoke is created by a crack that allows exhaust gases to seep through the cylinder crack instead of discharging smoke through the smoke exhaust pipe.

Smoke may also be accompanied by significant performance issues such as idling or reduction in power.

2) Engine Overheating

The engine overheating is one of the main symptoms of a cracked cylinder block. The engine may also overheat due to some other causes such as a blown head gasket, bad EGR valve, radiator failure, or low engine oil.

As the engine block cracks, the coolant leaks from it due to that coolant level goes down, and the engine overheats. The engine overheating is a very serious issue. As your vehicle engine overheats, you must stop the vehicle and inspect the reason for overheating.

3) Temperature Gauge

The high-temperature reading on the temperature gauge meter is a sign of a bad cylinder block.

The temperature gauge is located on the dashboard of your car. This gauge shows the temperature of your engine. As the engine block cracks, the coolant leaks, which leads to engine overheating. As the engine overheats, the temperature gauge trips into the red zone, which shows, your engine temperature is very high, and it is in danger. Don’t drive a vehicle with an overheated engine.

4) Oil Leaks

When you park your car in the driveway, take a look under your car. If you notice small drops of oil or puddles underneath the car, there are high chances that you have a cracked cylinder block. As the block cracks, the oil can seep through the cracks and drop onto the floor. The oil may also leak due to a blown head gasket or engine overheating.  

5) Coolant and Oil Mixing

After completing an oil change or coolant flush, you must pay attention to the color of the fluid being removed to restore it to its original appearance. If the oil and coolant are mixed, it may become a cloudy white liquid. This symptom shows that you have a cracked block due to that oil and coolant are mixing.  

6) Poor Engine Performance

A reduction in engine performance is one of the main signs of a cracked engine block. A cracked engine block may affect the engine compression, which may lead to insufficient combustion pressure. This issue generally leads to rough idle conditions and a significant reduction in fuel efficiency.

6) Seeing a Crack in the Block

You should inspect the block visually to confirm the crack in the block. If you can’t do it yourself, you may hire a technician for this job.

What causes an engine block to crack?

An engine cylinder block may crack due to multiple reasons. Following are the most common causes of a cracked engine block:

1) High heat

The continuously high temperature or overheating of the engine is one of the major causes of engine block cracking. The engine may overheat due to a blown head gasket, oil leak, low coolant, low engine oil, coolant leak, or faulty radiator.

The water pump is another cause of engine overheating. When the water pump fails, it doesn’t pump coolant throughout the engine, which leads to engine overheating and generates cracks in the block.

2) Low Temperature

If the engine temperature is too low, the engine block can crack. The cylinder block cracks, especially in cold weather, if the coolant is not working properly or freezes. This is a most common problem in older cars with older coolant.

When coolant freezes, it expands and puts pressure on the engine block walls and generates micro-cracks.

3) Manufacturer Defect

A minor mistake in manufacturing the engine block may generate cracks in the block. The block is formed by using the molding process. A minor fault or mistake in the molding process may reduce the engine block area or other defects that can lead to cracks in the engine block.

How to Fix a Cracked Engine Block?

Following are the most common methods to fix a cracked cylinder block:

1) Commercial Sealants

The commercial sealant is one of the best options when your block has small cracks.

  1. To fix the cracks, mix sealant with the coolant.
  2. Now turn on the engine so that coolant and sealant can flow throughout the engine.
  3. After some time, the product starts to work and seals the cracks. The technique only works for small cracks but not for large cracks.

2) Welding

The welding process is the best option if your engine block has large cracks. You can rewelded your block to seal cracks. The repairing process of the cylinder block needs special tools. You must hire a certified welder to weld the block because welding can easily damage the entire engine block.

3) Cold Welding Patches

The patching process uses adhesives and epoxy to seal the cylinder block cracks. However, this method can only use to seal the cracks for a short time. It can’t seal the cracks for a long time. The high temperature may damage the patching repair and lead to further damage.

4) Cold Metal Stitching

This is one of the most expansive processes. In this method, metal pieces are stitched together. The high temperature of the engine can’t affect the stitching repair. However, you need a specialist for this process.  

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